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aliina [53]
3 years ago
10

The number above the elements symbol is the elements atomic number. Match each element with the number of valence electrons it h

as Al S Na Si Mg P 4 5 3 6 2
Chemistry
2 answers:
tino4ka555 [31]3 years ago
8 0

Answer:

Aluminium has 3, Sulfur has 6, Sodium has 1, Silicon has 4, Magnesium has 2 and Phosphorous has 5 valence electrons.

Explanation:

Natali5045456 [20]3 years ago
4 0

<u>Answer:</u> Aluminium has 3, Sulfur has 6, Sodium has 1, Silicon has 4, Magnesium has 2 and Phosphorous has 5 valence electrons.

<u>Explanation:</u>

Valence electrons are defined as the electrons which are present in the outermost shell of an element. This can be determined very well from the electronic configurations of the elements.

The given elements are the elements which belong to the same period which is Period 3.

Electronic configuration of the given elements:

Al(Z=13)=1s^22s^22p^63s^23p^1

S(Z=16)=1s^22s^22p^63s^23p^4

Na(Z=11)=1s^22s^22p^63s^1

Si(Z=14)=1s^22s^22p^63s^23p^2

Mg(Z=12)=1s^22s^22p^63s^2

P(Z=15)=1s^22s^22p^63s^23p^3

Hence, from the electronic configurations, Aluminium has 3, Sulfur has 6, Sodium has 1, Silicon has 4, Magnesium has 2 and Phosphorous has 5 valence electrons.

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Answer:

A

Explanation:

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3 years ago
What type of wave do the contractions of the snake muscles make as the snake moves forward
S_A_V [24]
Actually, there are four kinds of reptile motion: 

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(taken from a user on Yahoo from Correct Answers)
3 0
4 years ago
Answer and work for this problem
MArishka [77]
We can write the balanced equation for the synthesis reaction as 
     H2(g) + Cl2(g) → 2HCl(g)

We use the molar masses of hydrogen chloride gas HCl and hydrogen gas H2 to calculate for the mass of hydrogen gas H2 needed:
     mass of H2 = 146.4 g HCl *(1 mol HCl / 36.46 g HCl) * (1 mol H2 / 2 mol HCl) * 
                           (2.02 g H2 / 1 mol H2)                        
                        = 4.056 g H2

We also use the molar masses of hydrogen chloride gas HCl and chlorine gas CL2 to calculate for the mass of hydrogen gas H2:
     mass of CL2 = 146.4 g HCl *(1 mol HCl / 36.46 g HCl) * (1 mol Cl2 / 2 mol HCl) *
                             (70.91 g Cl2 / 1 mol Cl2)
                          = 142.4 g Cl2 

Therefore, we need 4.056 grams of hydrogen gas and 142.4 grams of chlorine gas to produce 146.4 grams of hydrogen chloride gas.
6 0
3 years ago
If a buffer solution is 0.220 M in a weak acid ( Ka=7.4×10−5) and 0.540 M in its conjugate base, what is the pH?
valkas [14]

Answer: the pH of the solution is 4.52

Explanation:

Consider the weak acid as Ha, it is dissociated as expressed below

HA     H⁺  +  A⁻

the Henderson -Haselbach equation can be expressed as;

pH = pKa + log( [A⁻] / [HA])

the weak acid is dissociated into H⁺ and A⁻ ions in the solution.

now the conjugate base of the weak acid HA is

HA(aq) {weak acid}     H⁺(aq)  +  A⁻(aq) {conjugate base}

so now we calculate the value of Kₐ as well as pH value by substituting the values of the concentrations into the equation;

pKₐ = -logKₐ

pKₐ = -log ( 7.4×10⁻⁵ )

pKₐ = 4.13

now thw pH is

pH = pKₐ  + log( [A⁻] / [HA])

pH = 4.13 + log( [0.540] / [0.220])

pH = 4.13 + 0.3899

pH = 4.5199 = 4.52

Therefore the pH of the solution is 4.52

6 0
3 years ago
For the reaction Na2CO3+Ca(NO3)2⟶CaCO3+2NaNO3 how many grams of calcium carbonate, CaCO3, are produced from 79.3 g of sodium car
Alexus [3.1K]

Answer:

74.81 grams of calcium carbonate are produced from 79.3 g of sodium carbonate.

Explanation:

The balanced reaction is:

Na₂CO₃ + Ca(NO₃)₂ ⟶ CaCO₃ + 2 NaNO₃

By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of each compound participate in the reaction:

  • Na₂CO₃: 1 mole
  • Ca(NO₃)₂: 1 mole
  • CaCO₃: 1 mole
  • NaNO₃: 2 mole

Being the molar mass of the compounds:

  • Na₂CO₃: 106 g/mole
  • Ca(NO₃)₂: 164 g/mole  
  • CaCO₃: 100 g/mole
  • NaNO₃: 85 g/mole

then by stoichiometry the following quantities of mass participate in the reaction:

  • Na₂CO₃: 1 mole* 106 g/mole= 106 g
  • Ca(NO₃)₂: 1 mole* 164 g/mole= 164 g
  • CaCO₃: 1 mole* 100 g/mole= 100 g
  • NaNO₃: 2 mole* 85 g/mole= 170 g

You can apply the following rule of three: if by stoichiometry 106 grams of Na₂CO₃ produce 100 grams of  CaCO₃, 79.3 grams of Na₂CO₃ produce how much mass of  CaCO₃?

mass of CaCO_{3} =\frac{79.3 grams of Na_{2} CO_{3} *100 grams of of CaCO_{3}}{106 grams of Na_{2} CO_{3}}

mass of CaCO₃= 74.81 grams

<u><em>74.81 grams of calcium carbonate are produced from 79.3 g of sodium carbonate.</em></u>

6 0
3 years ago
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